FJ1100 fork conversion

[bikerphil]

Went riding today with another member from the board. I rode his 2H7 and he rode my 2H7 with the FJ forks. I needed some input from someone else to solve a few handling glitches. Both of us agreed that there was too much front suspension sag, even with the preload adjusters at the firmest setting. Tonight I put some 1/2" tall spacers and some washers on top of the springs. I took her for a ride tonight and what an improvement. It's just getting better every day. Now I'm running about 25mm of sag, which I have read is a good amount for street riding. The bike sits a bit higher now and corners way better. The experimentation continues....

[bikerphil]

Did some re-valving on the rebound circuit today. The lightest stock setting was a little too stiff, so I added an additional soft setting by using a #33 drill bit. I also had another set of forks that were never disassembled before which I stole some bushings and wave washers out of. The newly rebuilt and modified forks are running super smooth and handling great. Still more testing to do.

[DGXSER]

congrats on the progress Phil!! Sounds like you will be cornering with the crotch rockets in no time!

[bikerphil]

Today, I installed Progressive fork springs in the FJ forks, and this puppy is handling great. There is a big difference in the windings of the springs. In the pic below, the stock spring with it's original spacer, and the Progressive spring stands alone....

[bikerphil]

Been doing some more front suspension tuning. I'm getting very close to finding the optimal damping setup. I've added Progressive springs and also removed the oil lock piece from both damping rods. With the piece in place, the compression damping would be too hard, even with 5W oil. With the piece gone, now I'm running 15W and got rid of about 90% of the fork bounce.

Oil lock piece in place, compression damping holes restricted...


Oil lock piece removed, compression damping holes unobstructed...


A cool gadget I came up with for draining the fork oil. It directs the angle down 45 degrees so the oil shoots downward into the drain pan, not across the garage, lol. I made it out of an old fork drain screw with the head cut off and a hole drilled thru it, and a drilled out grease fitting.




Here's the 79 with the FJ1100 forks...

[Cobia]

Watch out for BikerPhil!!!

Hey Bro....
You're going to be dangerous at the Tail of the Dragon this summer!!!

[Cobia]

Tottally Imppressive

Yesterday I had the opportunity to try out Phil's modified bike and all I can say is a big WOW!! This baby now corners as if on rails with absolutely no frame wallowing. This mod is truely impressive.
Awesome mod Phil, you've really outdone yourself with this one.

[bikerphil]

Hey bro, thanks for the compliment. Yeah, I'm really enjoying riding this bike again. My poor Special just sits now and doesn't get ridden very often these days, lol. One thing I had to do was to make some mirror extensions. I couldn't see anything directly behind me, but now the problem is solved.

[WMarshy]

Awsome thread Phil, I now know what Im going to save my money for. I was considering buying a TKat fork brace but I am reconsidering that. This mod might come next winter, I hope I have a garage by then!

You should make this a tech tip if you have enough pics and the patients to write a step by step!

[dontlikeoc]

Beautiful mod. My kudos to you.

[bikerphil]

Thanks guys, I'll write somthing up once it's totally dialed in. I've run this mod for about 3K miles so far. Still tinkering a little with springs and fluid damping. Gotta make some permanent axle spacers too, running it with a few washers in there lol, but she's rock solid. This bike is a blast to ride this way. The FJ1100 forks can be had cheap if you keep your eyes open, the FJ guys take 'em off and upgrade to the later 89 + up 1200 forks, so they pretty plentiful. There is no real difference between them, other than the caliper and axle mounts.

[bikerphil]

Ok, latest improvement to this mod. I decided to put in some fork cartridge emulators. The correct emulators are about $175 a pair from Racetech. After doing some reading on their site, they mentioned that a adapter spacer can be made to fit an emulator to a damper rod that they don't have an application for. Got me to thinking, MikesXS sells emulators for $50 a pair, and all I'd have to do is come up with an adapter collar. Here's the oil lock piece for the anti-dive that I'd removed some time back...



It just happens the mike's emulator is the exact size to fit in the old oil lock piece...



I needed some way for it to sit up high enough from the damper rod to clear the rebound adjuster, so I added a piece of 1" PVC which was a perfect fit after a little sanding on the inside....



I had to add a thin washer also to sit in between the PVC spacer and the damping rod. Here's the emulator and the custom spacer...



Emulator sitting inside spacer, top view....



Emulator in spacer, bottom (damper rod side) view....



Also, the damper rods had to be drilled with larger holes to bypass the original circuit, to let the emulators do the work. Right now i'm running 20W fork oil and the emulators set at 3 turns out, 2 turns out is recommended street setting, and 4 turns out is recommended race setting. I'm also running Sonic straight wound springs witch are a bit narrower than stock, so they sit just fine on the new smaller emulators. Very nice improvement so far, but still in the testing stage.

[81xsproject]

NICE! You're getting closer and closer to talking me into this mod. $50 emulators is a major advance. Are those the stock clipons? Do they give you any adjustability as far as the angle? Great experimentation by the way. Oh, one more question; how is the front height compared to stock?

[crazy steve]

This would be a good one to condense down and move to the 'mods' section... what say Mr (or Ms!) Moderator?

'78E original owner

[bikerphil]

Are those the stock clipons? Do they give you any adjustability as far as the angle? how is the front height compared to stock?

Yes they are the stock clip-ons. They can be rotated slightly back or forward if the locating screw (useless) is left out. The ride height is about 1" lower, but these forks don't dive anywhere as much as stock units with Progressive springs. These Mike's emulators are small diameter so the stock springs (junk) can't be used.